The invention relates to a method for cleaning the fountain solution of a printing press with an automatically emptying separator, which separates the dirt particles and oil residues from the fountain solution and supplies them, as a mixture of dirt and fountain solution, to a dirt and fountain solution container and passes the remaining fountain solution into a fountain solution storage container.
In offset printing, the fountain solution serves to moisten the rollers, while they take up and transfer printing ink. Generally, the fountain solution consists essentially of water with an addition of alcohol and further additives. During the printing process, the fountain solution is exposed increasingly to contamination by taking up ink residues, dust, etc. On the other hand, every effort is made to re-use the fountain solution, since the water consumption and the costs of the additives, as well as, on the other hand, the disposal costs, can be kept within limits in this way. For this reason, fountain solution systems are cycled in many cases. Generally, the fountain solution is filtered or otherwise subjected to cleaning processes after use and then returned to a fountain solution tank. At the same time, the ratio, in which the water and additives are mixed, can also be adjusted once again. The cleaning of the fountain solution by a centrifugal separator, in which the dirt particles are separated from the fountain solution, is also known. Separators of this type, as embodiments with self-emptying facilities, also exist (DE 199 55 624 A1).
The separation of the mixture of fountain solution and dirt particles in the separator, of course, results in a product, which, as before, contains a relatively high proportion of reusable fountain solution.
An intensification of the cleaning process was attained with the help of filters, which are frequently used in practice. Filters are used in the form of filter mats, belt filters, filter bags, etc.
These filter materials represent consumable materials and, because they have to be purchased as well as, later on, disposed of, are associated with costs, especially also because of the need to have the filter materials exchanged regularly by the use of personnel.